JP2514203B2 - Vehicle hydraulic transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hydraulic transmission for a vehicle.

(Prior Art) In various vehicles such as lawn mowers and cultivators, a power source such as an engine or an electric motor is arranged at a position separated from the drive wheels, and the power of the power source is an oil pump, an oil motor, or the like. The one in which the speed is changed by a hydraulic transmission and transmitted to the driving wheels is disclosed in Japanese Patent Publication No. 38-7172 and Japanese Patent Publication No. 50-33.
It is known from publication 283.

(Problems to be Solved by the Invention) However, when the output shaft of the oil motor is directly connected to the axle of the driving wheel as in Japanese Patent Publication No. 387172,
There is a problem that a large capacity oil pump and oil motor must be used.

Further, in Japanese Patent Publication No. 50-33283, a reduction mechanism is provided to reduce the size of the oil pump and the oil motor.
Since a case is provided separately from the reduction case that houses the speed reduction mechanism, and the oil pump and oil motor are housed in this case, the number of parts increases and the hydraulic transmission becomes larger, and the oil pump and oil There was a problem that the cooling performance of the motor was poor.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to ensure a cooling property of an oil pump and an oil motor and to achieve compactness while suppressing an increase in the number of parts. The present invention provides a hydraulic transmission.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the structure of the present invention is applied to a vehicle in which a power source 9 such as an engine or an electric motor is provided at a position separated from the drive wheel 5, 33 side, reduction mechanism connected to the axle 33
A reduction case 21 accommodating 19 is provided, an oil pump 15 driven by the power of the power source 9 is attached to the outer wall surface of the reduction case 21, and the reduction pump 21 is driven by the power of the oil pump 15.
An oil motor 17 that drives 19 is attached to the outer wall surface of the reduction case 21, at least one of the oil pump 15 and the oil motor 17 is a variable displacement type, and the inside of the reduction case 21 is the oil pump 15 and the oil motor 17. In the oil tank, the oil passage connecting the oil pump 15 and the oil motor 17 is formed in the wall portion of the reduction case 21.

(Operation) Since the reduction mechanism 19 is provided between the oil motor 17 and the axle 33 of the drive wheel 5, the oil pump 15 and the oil motor 17 having a small capacity can be used.

Further, since the oil pump 15 and the oil motor 17 are arranged by using the reduction case 21 on the side of the axle 33 of the drive wheel 5, the increase in the number of parts is suppressed and the hydraulic transmission 13 is made compact. Can be planned.

Also, on the outer wall surface of the reduction case 21, an oil pump
15, the oil motor 17 is attached, so the oil pump 15,
Excellent cooling of the oil motor 17.

Moreover, since the oil passages of the oil pump 15 and the oil motor 17 are formed in the wall portion of the reduction case 21, the oil passage structure can be simplified.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

1 is a side view of the lawn mower, FIG. 2 is a left side view of the hydraulic transmission, FIG. 3 is a right side view of the same, and FIG. 4 is a developed view of the same.

1 is a walking type power lawn mower, 3 is a front wheel, 5 is a rear wheel,
7 is a steering wheel, the engine 9 is arranged between the front and rear wheels 3, 5,
Rotate the lawn mowing cutter 11 by engine power,
Further, the left and right rear wheels 5 are driven via the hydraulic transmission 13 by the engine power.

 The hydraulic transmission 13 is arranged between the left and right rear wheels 5.

The hydraulic transmission 13 includes an oil pump 15 driven by engine power, an oil motor 17 driven by the oil pump 15, a speed reduction mechanism 19, a reduction case 21, and the like.

The reduction case 21 is an open case body on the right side
23 and a lid 25 attached to the right side of the case body 23, and the reduction chamber 27 accommodates a reduction mechanism 19 including a gear 29 having a small diameter and a gear 31 having a large diameter.

Oil is injected into the reduction chamber 27, and the reduction case 21 also serves as an oil tank.

The axle 33 of the rear wheel 5 is laterally provided below the reduction case 21 via a seal material 35, and the gear 31 is attached to the axle 33.

The oil pump 15 is located on the front of the top of the reduction case 21.
The oil motor 17 is attached to the left side surface 39 at the upper part of the reduction case 21.

In the embodiment, the swash plate type variable displacement axial piston pump is used as the oil pump 15, and the swash plate type fixed displacement axial piston motor is used as the oil motor 17.

The oil pump 15 includes a pump case 41 and a pump case 41.
A drive shaft 43 disposed therein, a swash plate 45 tiltably incorporated in the pump case 41, a cylinder block 47 that rotates integrally with the drive shaft 43, and a swash plate 45 incorporated in the cylinder block 47. A plurality of pistons 49 that reciprocate while rotating on the thrust bearing 46, a valve plate 55 having a suction port 51 and a discharge port 53, and the like.

The front end of the drive shaft 43 is projected to the front of the pump case 41,
An output shaft 59 on the engine side is connected to this portion via a universal joint 57.

The inclination angle of the swash plate 45 is set by swinging the lever 63 with the pin 61 as a fulcrum, and the swinging of the lever 63 is performed by operating the shift lever 65 provided on the handle 7 side. In the embodiment, it is possible to switch between forward, neutral and reverse, and 66 in FIG. 1 denotes a throttle lever.

The oil motor 17 includes a motor case 67 and a motor case 67.
An output shaft 69 disposed therein, a swash plate 71 incorporated in a motor case 67 and configured by thrust bearings, a cylinder block 73 that rotates integrally with the output shaft 69, and a swash plate incorporated in the cylinder block 73. A plurality of pistons 75 that reciprocate while rotating on 71, and a valve plate 81 having an inlet port 77 and an outlet port 79 are provided.

The right end of the output shaft 69 is projected into the reduction chamber 27, and the gear 29 is attached to this portion.

Next, the oil passages of the oil pump 15 and the oil motor 17 will be described with reference to FIGS. 5 to 8.

FIG. 5 is a view of the reduction case viewed from the direction of arrow V in FIG. 2, FIG. 6 is a view in the direction of arrow VI of FIG. 5, and FIG. 7 is VI of FIG.
Fig. 8 is a sectional view taken along the line I-VII and Fig. 8 shows a hydraulic circuit diagram.

First, the suction passage 83 that supplies oil to the oil pump 15.
Has an oil passage 87 whose lower end opens in the reduction chamber 27 and extends upward in the left side wall 85 of the reduction case 21, and an oil passage 87.
Connected to the oil passage 89 extending leftward, an oil passage 91 connected to the left end of the oil passage 89 extending vertically, and an oil passage 93 connected to the upper end of the oil passage 91 extending forward and backward. And an oil passage 95 which is connected to the front end of the oil passage 93, extends rightward and is connected to the suction port 51.

An oil filter 97 is attached to the opening 84, and 99 in the figure indicates a shielding plate.

The oil passage 101 connecting the discharge port 53 of the oil pump 15 and the inlet port 77 of the oil motor 17 has a discharge port 53.
Connected to the oil passage 103 and extending to the left side, an oil passage 105 connected to the left end of the oil passage 103 and extending downward, and an oil connected to the oil passage 105 and extending rearward to be connected to the inlet port 77. Comprised of path 107.

The oil passage 109 connecting the outlet port 79 of the oil motor 17 and the suction port 51 of the oil pump 15 includes an oil passage 111 connected to the outlet port 79 and extending upward, and the oil passage connected to this oil passage 111. It consists of 93 and oil passage 95,
The oil pump 15 and the oil motor 17 are connected by a closed circuit.

The lower end of the oil passage 91 forming the suction passage 83 is the oil passage 107.
And check valves 113 and 115 are provided above and below the oil passage 91, respectively.

Further, the oil passage extends vertically in the rear portion of the left wall portion 85.
An oil passage 117 connected to 93, 107 and an oil passage 119 connected to the oil passage 117 and opening in the reduction case 21 are formed.

 A switching valve 121 is inserted in the oil passage 117.

The switching valve 121 is connected to a neutral lever 123 provided on the handle 7 side via a wire 125 and an arm 127.
27 is disposed on the left side of the upper surface 129 of the reduction case 21 via a bracket 131.

In the embodiment, the switching valve 121 includes a shaft portion 121A and two large diameter portions 1
An oil passage 121D that connects the peripheral surface of the upper large diameter portion 121B and the peripheral surface of the shaft portion 121A is formed by the spool valve composed of 21B and 121C. Then, with the neutral lever 123 swinging to the handle 7 side, as shown in FIG.
As shown in FIG. 9, the oil passages 93, 107, 119 are cut off from each other via C, and the neutral lever 123 is separated from the handle 7, as shown in FIG.
The arm 127 is configured to communicate with each other and the spring 127 biases the arm 127 in a direction in which the oil passages 93, 107, 119 communicate with each other.

 Next, the operation of the hydraulic transmission 13 will be described.

Drive shaft of the oil pump 15 by the output shaft 59 on the engine side
43 turns.

When moving forward, the cylinder block is rotated by the rotation of the drive shaft 43.
47 pivots to reciprocate each piston 49 to transfer oil to the oil filter 97, oil passages 87, 89, 91, check valve 113, oil passage 93,
95, suction port 51, discharge port 53, oil passage
Inlet port 7 of oil motor 17 via 103, 105, 107
Supply to 7. And each piston 75 of the oil motor 17
Is reciprocated to rotate the cylinder block 73, the output shaft 69 is rotated by the rotation of the cylinder block 73, and the power of the engine is transmitted to the axle 33 via the reduction mechanism 19. The oil is circulated from the outlet port 79 to the suction port 51 of the oil pump 15 via the oil passages 111, 93 and 95. This flow is the eighth
This is indicated by a solid arrow in the figure.

Gear shifting is performed by changing the inclination angle of the swash plate 45 by the shift lever 65, and when neutral, the swash plate 45 is perpendicular to the drive shaft 43, the piston 49 does not reciprocate, and oil does not circulate.

When moving backward, the inclination angle of the swash plate 45 is opposite to the inclination angle when moving forward, and oil is passed through the oil passages 87, 89, 91, the check valve 115,
The oil is sucked from the discharge port 53 through the oil passages 107, 105 and 103, and is supplied to the outlet port 79 of the oil motor 17 through the suction port 51 and the oil passages 95, 93 and 111.

Then, the pistons 75 of the oil motor 17 are reciprocally moved to rotate the cylinder block 73 and the output shaft 69 in the opposite direction to the forward movement, thereby rotating the axle 33 in the reverse direction. Oil is circulated from the inlet port 77 to the discharge port 53 of the oil pump 15 via the oil passages 107, 105 and 103. This flow is shown by a dotted arrow in FIG.

When moving forward and backward, the neutral lever 12
If 3 is swung in the direction away from the handle 7, the oil is not supplied to the oil motor 17 by the operation of the switching valve 121, the oil motor 17 is stopped, and the axle 33 becomes free.

In the above, since the reduction mechanism 19 is arranged between the output shaft 69 of the oil motor 17 and the axle 33 of the rear wheel 5, the oil pump 15 and the oil motor 17 are for low torque high speed rotation,
That is, a small size is sufficient, and these hydraulic devices 15 and 17 can be made compact.

Further, since the reduction case 21 on the side of the axle 33 that houses the reduction gear mechanism 19 is used and the oil pump 15 and the oil motor 17 are attached to the reduction case 21, an increase in the number of parts is suppressed and the hydraulic transmission 13 is suppressed. Can be made compact.

Also, on the outer surface of the reduction case 21, the oil pump 1
5, because the oil motor 17 is attached, the oil pump 15,
Excellent cooling of the oil motor 17.

Moreover, since the oil passages of the oil pump 15 and the oil motor 17 are formed in the wall portion of the reduction case 21, the oil passage structure can be simplified.

In addition, a hydraulic transmission 13 is provided at a position separated from the engine 9.
Since the oil pump 15 and the oil motor 17 are not directly subjected to the vibration of the engine 9, the durability of the oil pump 15 and the oil motor 17 can be improved.

In the embodiment, the case where the axial piston pump is used as the oil pump 15 and the axial piston motor is used as the oil motor 17 has been described, but the types of the oil pump 15 and the oil motor 17 are not limited to those of the embodiment. Other types may be used, and at least one of the oil pump 15 and the oil motor 17 may be a variable displacement type.

Further, in the embodiment, the check valves 113 and 115 are provided in the oil passage to perform the forward and backward movements, but the check valves 113 and 115 may not be provided and the circuit may be configured to perform only the forward movement.

The oil passage connecting the oil pump 15 and the oil motor 17 may be a closed circuit or an open circuit.

(Effects of the Invention) As is clear from the above description, according to the present invention, it is possible to secure the cooling performance of the oil pump and the oil motor, and to suppress the increase in the number of parts and to achieve the hydraulic pressure of the vehicle. Type transmission can be obtained.

[Brief description of drawings]

1 is a side view of the lawn mower, FIG. 2 is a left side view of the hydraulic transmission, FIG. 3 is a right side view of the same, FIG. 4 is a same expanded view, and FIG. 5 is a second view. Of the reduction case viewed from the direction of arrow V in FIG. 6, FIG. 6 is a view in the direction of arrow VI of FIG. 5, and FIG.
VII-VII sectional view, FIG. 8 is a circuit diagram, and FIG. 9 and FIG. 10 are sectional views showing the operating state of the switching valve. In the drawing, 5 is a rear wheel, 7 is an engine, 13 is a hydraulic transmission, 15 is an oil pump, 17 is an oil motor, 19 is a reduction mechanism, 21 is a reduction case, 33 is an axle, 113, 115 are check valves, 121 Is a switching valve.

Claims (1)

(57) [Claims] 1. A vehicle in which a power source such as an engine or an electric motor is provided at a position separated from a drive wheel, and a reduction case accommodating a reduction mechanism connected to the axle is provided on the axle side of the drive wheel, An oil pump driven by the power of a power source is attached to the outer wall surface of the reduction case, an oil motor driven by the power of the oil pump and driving the reduction mechanism is attached to the outer wall surface of the reduction case, At least one of the oil pump and the oil motor is a variable displacement type, the inside of the reduction case is configured as an oil tank of the oil pump and the oil motor, and the oil passage connecting the oil pump and the oil motor is formed with a wall portion of the reduction case. A hydraulic transmission for a vehicle, which is characterized in that: